Hydrogen permeation/separation thin membrane

Abstract

A hydrogen permeation/separation thin membrane including a Ni—Ti—Nb alloy. The Ni—Ti—Nb alloy is a cast foil material obtained by roll quenching and a refining heat treatment. The membrane has a thickness of 0.07 mm or less. The Ni—Ti—Nb alloy has the following: (a) a composition consisting of 10 to 47 atomic % of Nb, 20 to 52 atomic % of Ti, and a remainder containing 20 to 48 atomic % of Ni and inevitable impurities; and (b) an alloy structure where fine particles of a Nb-based solid solution alloy, in which Nb forms a solid solution with Ni and Ti in Nb, are dispersed in a basic structure made of a Ni—Ti(Nb) intermetallic compound formed of a solid solution of a Ni—Ti intermetallic compound, in which part of Ti thereof is replaced by Nb.

1. A hydrogen permeation/separation thin membrane comprising a Ni—Ti—Nb alloy,
 said Ni—Ti—Nb alloy being a cast foil material obtained by roll quenching to a thickness of 0.07 mm or less, and then being subjected to a refining heat treatment, and 
 said Ni—Ti—Nb alloy having: 
 (a) a composition consisting of 10 to 47 atomic % of Nb, 20 to 52 atomic % of Ti, and a remainder containing 20 to 48 atomic % of Ni and inevitable impurities; and 
 (b) an alloy structure where fine particles of a Nb-based solid solution alloy, in which Nb forms a solid solution with Ni and Ti, are dispersed in a basic structure made of a Ni—Ti(Nb) intermetallic compound formed of a solid solution of a Ni—Ti intermetallic compound, in which part of the Ti thereof is replaced by Nb. 
 
     
     
       2. A hydrogen permeation/separation thin membrane comprising a Nb—Ti—Ni alloy,
 said Nb—Ti—Ni alloy being a cast foil material obtained by roll quenching to a thickness of 0.07 mm or less, and then being subjected to a refining heat treatment, and 
 said Nb—Ti—Ni alloy having: 
 (a′) a composition consisting of 10 to 32 atomic % of Ni, 15 to 33 atomic % of Ti, and a remainder containing 48 to 70 atomic % of Nb and inevitable impurities; and 
 (b′) an alloy structure where fine particles of a Ni—Ti(Nb) intermetallic compound formed of a solid solution of a Ni—Ti intermetallic compound, in which part of the Ti thereof is replaced by Nb, are dispersed in a basic structure made of a Nb-based solid solution alloy, in which Nb forms a solid solution with Ni and Ti. 
 
     
     
       3. A hydrogen permeation/separation thin membrane according to  claim 1 , wherein roll quenching is performed under conditions where a molten alloy comprising Nb, Ni and Ti is sprayed from a slit having a dimension of 20 mm in length and 0.3 mm in width at an injection pressure of 0.05 MPa onto the surface of a water-cooled copper roll rotating at a roll rate of 20 m/sec to form cast foil materials of the Ni—Ti—Nb alloy. 
     
     
       4. A hydrogen permeation/separation thin membrane according to  claim 1 , wherein the refining heat treatment is performed in a vacuum of 10 −2  Pa or less under the conditions where the foil material is retained at a predetermined temperature within the range of 300 to 1,100° C. for 5 hours. 
     
     
       5. A hydrogen permeation/separation thin membrane according to  claim 2 , wherein roll quenching is performed under conditions where a molten alloy comprising Nb, Ni and Ti is sprayed from a slit having a dimension of 20 mm in length and 0.3 mm in width at an injection pressure of 0.05 MPa onto the surface of a water-cooled copper roll rotating at a roll rate of 20 m/sec to form cast foil materials of the Ni—Ti—Nb alloy. 
     
     
       6. A hydrogen permeation/separation thin membrane according to  claim 2 , wherein the refining heat treatment is performed in a vacuum of 10 −2  Pa or less under the conditions where the foil material is retained at a predetermined temperature within the range of 300 to 1,100° C. for 5 hours.